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      08-02-2015, 10:01 PM   #1
dishy
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Question about 8 speed ZF gear changes

When I change manually, I notice on the instrument cluster it telling me what gear I should be in, something along the lines of: M5 > 7. This tells me that I'm in 5th but for what I am doing I should be in 7th.

Is it possible to tell the gear box to go directly to 7th? I can tap the upshift twice but you feel two gear changes. I've tried holding the upshift paddle to see if it would go directly to 7th (just an example) but it only shifted once, to 6th.

I suppose there may be no way to do these kinds of shifts manually, but wanted to ask the question.
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      08-03-2015, 01:05 AM   #2
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By the sounds of this, you are using Eco pro mode (display tells you which gear to select). In that case don't use the paddles. Just let the box do all the work.
The design of the paddle shifter is to only allow one gear shift up or down at a time.
This is so you cannot over rev the engine or put too much stress on the box. There is an override (engine & box) if you try to go beyond the gear selected set parameters.
If you are in manual mode (shifter moved over to the left on a RHD) it is best to use 'Sport' mode so you can go though all 8 gears with the paddles.
Then the instrument cluster only shows the gear selected.
The engine will normally labor if it is a too higher gear.
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      08-03-2015, 09:17 PM   #3
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Cheers for the info, that makes sense.

The gear select recommendations happen in comfort mode too. I'll check on the way home tonight but I think they may also happen on sport mode.
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      08-12-2015, 08:56 PM   #4
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Gear recommendations happen regardless of sport or eco mode.
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      08-13-2015, 01:32 AM   #5
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Sequential shifting

The paddles replicate a sequential gearbox....the logic always taking you to the next gear up or down, as long as that shift is safe i.e doesn't over rev or lug the engine. If you're in 5th and want 7th click the upshift paddle twice.

In auto mode, the gearbox can hop from say 4th to 7th directly without engaging the intermediate ratios, the shift depending on the mode and gas pedal settings
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      08-17-2015, 02:57 AM   #6
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Cheers SteveC
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      08-18-2015, 06:13 PM   #7
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It must be a LCI change.
In mine the sport auto only shows the gear selected in 'sport' and keeps it there unless you stop (goes back to M1).
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      08-19-2015, 01:57 AM   #8
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Can you let me know what LCI is? BTW I have the 2nd generation 8 speed ZF gearbox so may be it's due to that?
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      08-19-2015, 02:04 AM   #9
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Quote:
Originally Posted by dishy View Post
Can you let me know what LCI is? BTW I have the 2nd generation 8 speed ZF gearbox so may be it's due to that?
Life Cycle Improvement, also known as facelift.
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      08-19-2015, 08:20 AM   #10
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I looked into this recently, interestingly (or not!) only certain models of 1 series have received the second generation 8HP50 box and others still have the earlier 8HP45 generation 1 box even after the LCI changes. It seems that the new 3 cylinder cars and B47 diesel 4s now have the gen 2 (8HP50) box and the slightly older petrol 4s and the big 6 (i.e. N generation engines) have the gen 1 box . It looks like they are transitioning over to the gen 2 box along with the transition to the B generation engine.

I believe the differences are very minor and include a wider ratio spread (7.8:1 vs 7.06:1), reduced oil pressure requirements and instant SS shutdown where the gen one needed a 1.5s wait, presumably to pressurise the hydraulics. The speed at up to which coasting is possible is also increased with gen 2 up to 160km/h but I can't offer exact figures on what it was previously.

Last edited by padders; 08-19-2015 at 08:30 AM..
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      08-19-2015, 10:06 AM   #11
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Quote:
Originally Posted by ovekvam View Post
Life Cycle Improvement, also known as facelift.
Do you really need to disregard your car that way? LCI is a "Life Cycle Impulse", precisely.
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      08-20-2015, 03:53 AM   #12
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Quote:
Originally Posted by padders View Post
I looked into this recently, interestingly (or not!) only certain models of 1 series have received the second generation 8HP50 box and others still have the earlier 8HP45 generation 1 box even after the LCI changes. It seems that the new 3 cylinder cars and B47 diesel 4s now have the gen 2 (8HP50) box and the slightly older petrol 4s and the big 6 (i.e. N generation engines) have the gen 1 box . It looks like they are transitioning over to the gen 2 box along with the transition to the B generation engine.

I believe the differences are very minor and include a wider ratio spread (7.8:1 vs 7.06:1), reduced oil pressure requirements and instant SS shutdown where the gen one needed a 1.5s wait, presumably to pressurise the hydraulics. The speed at up to which coasting is possible is also increased with gen 2 up to 160km/h but I can't offer exact figures on what it was previously.
Hi Padders, where have you found this info from please mate? From the very limited google research I have done, the gen 2 gearbox is still an 8HP45 and I also though the gear ratios remained the same.
Regarding the certain models, I would think that it was more by chance but had this criteria:
- since gen 2 box released mid 2014, only cars manufactured after this date could possibly have them
- BMW stock of gen1 boxes would need to have run out before BMW would have ordered more 8HP gearboxes, which would have been gen2

So, I think that it may have been a little while after the gen2 release date, however my car was actually manufactured in late 2014 but I'm sure it has the gen2 box as engine shutdown is instant and sometimes before the car has fully come to a complete settled stop. I think the A.S.S should wait 0.5s tbh.
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      08-20-2015, 08:06 AM   #13
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Quote:
Originally Posted by dishy View Post
Hi Padders, where have you found this info from please mate? From the very limited google research I have done, the gen 2 gearbox is still an 8HP45 and I also though the gear ratios remained the same.
Regarding the certain models, I would think that it was more by chance but had this criteria:
- since gen 2 box released mid 2014, only cars manufactured after this date could possibly have them
- BMW stock of gen1 boxes would need to have run out before BMW would have ordered more 8HP gearboxes, which would have been gen2

So, I think that it may have been a little while after the gen2 release date, however my car was actually manufactured in late 2014 but I'm sure it has the gen2 box as engine shutdown is instant and sometimes before the car has fully come to a complete settled stop. I think the A.S.S should wait 0.5s tbh.
Hi

I formed the opinion I posted above via research at http://www.realoem.com, http://www.automobile-catalog.com/ and also http://www.zf.com

Real OEM shows that some models are currently fitted with the second gen '50' box as per the 5 series update of mid 2014 and other models still have the earlier '45' box. The second link above lists gear ratios for each model and this data supports realoem since it can be shown that the models with the 50 box have the taller top gear and the 7.8:1 spread. The other models with the '45' box such as the 120i and M135i have the earlier 7.07:1 ratio spread. I am not claiming it is gospel but I would be surprised if I am wrong.

On the press release for the second gen 8HP50 box ZF specifically state that the ratio spread has been widened to 7.8:1 so it seems to me that if a box has the narrower 7:1 spread then its a gen 1 8HP45

See: http://www.zf.com/corporate/en_de/pr...sp?newsId=3885

What I can't be sure of is if there is a second gen '45' box around but I doubt is as the '45' now being fitted has the earlier gen 1 ratio spread so is presumably a gen 1 box. In addition the wiki page for the zf8hp lists the 45 as gen 1 and the 50 as gen 2 but this hasn't been updated for a while so would only consider it at best circumstantial evidence!

In summary, it seems to me that if you have a B gen engine you get the GA8HP50, if you have a N engine you get the 45. This of course may change at any point or indeed may have changed already. Make of that what you will!


ps I am talking about Euro spec cars, I have no idea if the Antipodean cars are similar or not!

Last edited by padders; 08-20-2015 at 08:46 AM..
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      08-23-2015, 10:50 PM   #14
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Hi Padders, I could not see any information relating to a HP50 in their products list.
The 8HP which supports 500Nm torque is the 8HP45 with a different torque converter for Diesels. After the 45 comes the 55. I expect the HP50 is a new gearbox addition and not a gen2 of HP45, and ZF didn't update their product list on their website, it seems. May be there is a reason for this, eg the different gear ratios you mention and is stated on the BMW 5 series write up.
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      08-24-2015, 01:14 AM   #15
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All you need is in the links I posted above. See:

http://www.zf.com/corporate/en_de/pr...sp?newsId=3885

Which is from ZF's own website, clearly names the 8HP50 and 8HP75 (third paragraph) and explains that they are the 2nd gen version of the 45 and 70. Also:

https://en.wikipedia.org/wiki/ZF_8HP_transmission

Which does the same but being wiki isn't as authoritative obviously and no I didn't write the page.
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      08-24-2015, 02:09 AM   #16
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Hi Padders, I checked the ZF link but I don't see on there where it states the 8HP50 as the name for the 2nd gen 8HP45. The article describes the 8HP50 as a different gearbox altogether with different gear ratios, for the 5 series BMW.
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      08-24-2015, 04:31 AM   #17
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I think we are splitting hairs here. You could indeed call the 8HP 50 a different box but it seems pretty clear to me from the press release that it is of the second generation of the 8HP line. As for just being a diesel version of the 45, that doesn't make sense since they also use the new 50 box on the petrol triple B38 engines too.

I am not sure why you find it hard to believe that it is a refinement of the 8HP box, seems pretty clear from the press release to me. They use the following:

'The successful 8HP 8-speed automatic transmission has been characterized by these advantages since the start of production in 2009. All of the advantages are now even more pronounced in the second generation that initially is in volume production since July 2014 in the BMW 520d. The new 8HP offers comprehensive further developments that range from lower drag torques and higher spread through to an improved torsional vibration absorption. Gradually, the new 8-speed automatic transmissions from ZF are being deployed in further models and with many automotive manufacturers worldwide.'

And:

'The new 8HP entered volume production at the start of July in the BMW 520d as the 8HP50 version that is designed for torques of up to 500 Nm. In the future, the 8HP75 will be part of the ZF portfolio for drives with even higher torque of up to 750 Nm.

Gradually, all further automotive manufacturers to whom ZF has already supplied the 8HP in over 1 000 vehicle applications will utilize the latest generation of the 8-speed automatic transmission.'
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      08-24-2015, 11:15 PM   #18
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Hi Padders, I think you are misunderstanding their text. Speaking specifically about the 8HP45, there are gen 1 and gen 2 boxes of the 8HP45. There are a few key differences to be able to tell them apart but effectively the gen2 is just an updated version of the same box. One key difference is the gen 1 had a A.S.S shutdown time lag of 1.5 seconds whereas the gen 2 is immediate. The 8HP50 seems to be a run of something new as it has different gear ratios, unlike the other 8HP line gearboxes which have the same gear ratios regardless of model number, ie: 8HPX where X relates to the capable torque input.

So, the 8HP50 is not the second generation of 8HP45's. I can see on documentation relating to my car that the gear ratios do not match that of the 8HP50 but they do match the 8HP45 (and others from this link in the technical information tab: http://www.zf.com/corporate/en_de/pr....shtml#tabs1-1).

I cannot find any technical information at all about the 8HP50. It's not listed in the link above.

I also read somewhere that the 8HP line is the 2nd generation of ZF 8 speed gearboxes, with reduced internal friction giving better fuel economy. In fact I believe it is mentioned in the ZF promo videos on their website.
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      08-25-2015, 01:05 AM   #19
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Quote:
Originally Posted by dishy View Post
Hi Padders, I think you are misunderstanding their text. Speaking specifically about the 8HP45, there are gen 1 and gen 2 boxes of the 8HP45. There are a few key differences to be able to tell them apart but effectively the gen2 is just an updated version of the same box. One key difference is the gen 1 had a A.S.S shutdown time lag of 1.5 seconds whereas the gen 2 is immediate. The 8HP50 seems to be a run of something new as it has different gear ratios, unlike the other 8HP line gearboxes which have the same gear ratios regardless of model number, ie: 8HPX where X relates to the capable torque input.

So, the 8HP50 is not the second generation of 8HP45's. I can see on documentation relating to my car that the gear ratios do not match that of the 8HP50 but they do match the 8HP45 (and others from this link in the technical information tab: http://www.zf.com/corporate/en_de/pr....shtml#tabs1-1).

I cannot find any technical information at all about the 8HP50. It's not listed in the link above.

I also read somewhere that the 8HP line is the 2nd generation of ZF 8 speed gearboxes, with reduced internal friction giving better fuel economy. In fact I believe it is mentioned in the ZF promo videos on their website.
And I think it is you who are misunderstanding the text. I haven't seen any info at all suggesting that there is a second version of the 8HP45 so if you have found any evidence of this I would be very interested to see it. It seems clear from the press release that the 8HP50 is second generation meaning what came before is first generation. The 8HP45/70/90 was the original design of 8HP thus is the first generation. The 8HP50/75 is the second generation. If you think otherwise, show me. Not being able to find info on a brand new updated product doesn't prove it doesn't exist, it shows that ZF are lousy at updating their website.

8HP is not IMO the name of second generation of the 8 speed it is the generic name for the ZF 8 speed gearbox family including first and second efforts, just as 6HP covered all the six speed boxes. If it is indeed the second generation name as you suggest, what the hell was the first gen called?

I think you are clutching at straws here mate, I really do.

Last edited by padders; 08-25-2015 at 01:12 AM..
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      08-25-2015, 03:40 AM   #20
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Maybe I can put this debate to bed. I have found a page by one of ZF's sub contractors which clearly states the relationship between the HP45 and HP50. See:

http://www.punchpowerglide.com/en/pr...p45-8hp50.html

They make both in Strasbourg. Convinced yet?
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      09-07-2015, 11:49 PM   #21
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Hi Padders, I thought I'd reach out to ZF directly before commenting any further as I grasped the tone of your email you were becoming a bit angry at the discussion. Thanks for the link too.

I confirmed with ZF that the 8HP50 is what is called the 2nd generation 8HP gearbox. So apologies for my misunderstanding here. However I have also found out that since the 8HP45 initial launch there have been many updates and improvements to the 8hp45. So, it is possible my M135 has an updated 8HP45 rather than the 8HP50, but it's not what is called a second generation 8HP45 like I first understood. I need to get the gearbox coding numbers off the casing to be able to identify and I don't have a ramp or any way of seeing it, so I can't tell which version of 8HP45 I have (if I have a 45). I'm still waiting on ZF to get back to me with regards to some questions I had about the characteristical differences between the 45 and the 50. I think the only way for me to know for sure is to see what RPM the engine is doing in a specific gear and specific speed as the gear ratios are different between the two boxes, and gear ratios have not been changed in the 8HP45.
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      09-07-2015, 11:52 PM   #22
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Another discovery regarding the gear changes on my M135, if I am in manual mode (gear lever to the left) the car will change up gear by itself when I am driving gently. I forgot I was in manual mode and pulled off from the lights gently. I noticed the car was waiting a while to change gear, I thought I was in sports mode somehow. When I looked at the dash the gear showed D and the car changed up gear but the selector was in manual. Just FYI.
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